Multi-purpose wellhead apparatus for oil wells



Feb. 19, 1963 D. U. SHAFFER ETAL 3,077,931

MULTI-PURPOSE WELLHEAD APPARATUS FOR OIL WELLS Filed Jan. 4, 1960 2Sheets-Sheet'l UN FIG. 4.

INVENTORS DONALD U. SHAFFER EUGENE C. GREENWOOD ATTORNEY. I

Feb. 19, 1963 Filed Jan. 4, 1960 D. u. SHAFFER ETAL 7,931 MULTI-PURPOSEWELLHEAD APPARATUS FOR OIL WELLS 2 Sheets-Sheet 2 INVENTORS. DONALD U.SHAFFER EUGENE C. GREENWOOD ATTORNEY.

United States Patent Ofltice 3,077,931 Patented Feb. 19, 1963 3,077,931MULTI-PURPOE WELLHEAD APFARATUS FOR 01L WELLS Donald U. Shatter, Bren,and Eugene C. Greenwood,

Corona Del Mar, Calih, assignors to Shatter Tool Works, Bren, Caiih, acorporation of California Filed Jan. 4, 1960, Ser. No. 4-34 1 Claim.(Cl. 16689) This invention relates to a multi-purpose wellhead apparatusadapted to be employed in connection with both flowing wells and pumpingwells.

An object of the present invention is to provide an improved wellheadapparatus which makes it possible to convert from flowing operation topumping operation, or to pull the tubing, without the necessity that theChristmas tree (or equivalent thereof) be disturbed in any Way.

Another object of the invention is to provide a wellhead apparatus whichreduces the danger involved in pulling the tubing, it being unnecessaryto place the Christmas tree in inoperative condition at any time.

A further object of the invention is to provide a wellhead apparatuswhich makes it possible to convert from flowing operation to pumpingoperation, or to pull the tubing, without danger of damage to API ringsand consequent leaks upon re-assembly.

A further object is to provide a highly simple and economical wellheadapparatus incorporating relatively few parts.

These and other objects and advantages of the invention will be morefully set forth in the following specification and claim, considered inconnection with the attached drawings to which they relate.

In the drawings:

FIGURE 1 is an elevational view of an apparatus incorporating theinvention, and connected for flow operation;

FIGURE 2 is a vertical sectional view of the upper portion of theapparatus illustrated in FIGURE 1, the section being taken on brokenline 2-2 of FIGURE 3;

FIGURE 3 is a horizontal section on line 33 of FIGURE 2; and

lGURE 4 is an elevation corresponding to FIGURE 1 but illustrating theapparatus connected for pumping operation.

Referring to the drawings, the invention is illustrated as incorporatedin a wellhead apparatus comprising a base (casing) head body it the legsitia for which are suitably anchored in concrete 11 disposed around theouter string 12 of casing. The base head body is sealingly mountedcoaxially over the upper end of the casing string 12, and comprises adownwardly-convergent frustoconical or tapered-bowl portion 13 adaptedto receive the slips 14 for the second and smaller-diameter string 1% ofcasing. The body it) further comprises an upper generally-tubularportion 17 extending upwardly from the tapered-bowl portion 1.3. Thesecond casing string 16 is shown as being cut off in approximately thesame plane as the upper end of tubular portion 17.

Mounted in the annulus between casing head portion 17 and the upper endof second casing string 16 is a lower rigid packer plate or ring 18,such plate being supported by a lower snap ring 19 and also by the fluidpressure therebeneath. An elasto-meric packing ring 21, having a radialdimension corresponding generally to that of the annulus, is mounted onthe packer plate 18 in order to seal off the annulus as will bedescribed hereinafter.

Supported on the packing ring or rubber 21 is a multipurpose orcombination body element 22 adapted to vent the annulus within secondcasing string 16, to discharge the well fluid which flows upwardlythrough the tubing string 23, and to compress the packing rubber 21 inorder to effect the above-indicated seal of the annulus within outercasing string 12. The multi-purpose body 22 is preferably an integralcasting having a generally tubular shape, the inner diameter of the tubebeing at least as large as the inner diameter of the second casingstring 16. The lower end of body 22 is formed with a radially-outwardlyextending flange 24 the lower surface of which has a shape correspondingto the upper surface of packing rubber 21. A plurality of cap screws 26are extended downwardly through suitable holes in flange 24 and packingrubber 21' and are threaded into suitable interiorlythreaded openings inthe lower packer plate 18. An upper snap ring 27 is mounted in bodyportion 17 upwardly adjacent flange 24 to insure against upward shiftingof the assembly due to factors such as excessive fluid pressure in theouter annulus.

The multi-purpose element 22 is necked-down slightly, in spaced relationabove the upper end of casing string 16, to create the downwardly-facingshoulder indicated at 23. A counterbore is provided in the upper end ofelement 22 in order to form an upwardly-facing radial shoulder 29adapted to seat a tubing hanger 31. More specifically, the tubing hangeris illustrated as having an upper radial flange 32 the peripheralportion of which rests on shoulder 29, the flange being beveled at itsupper portion to form an upwardly-convergent peripheral surface portion33. Surface portion 33 is adapted to be engaged by the conical innerends 34 cf radially-inwardly extending lock screws 36 which are threadedinto boss portions 37 of element 22. Four such boss portions 37 andcorresponding lock screws 35 are illustrated in FIGURE 3 as being spacedat ninety-degree intervals, each lock screw having a squared outer endso that a wrench may be employed to thread the screws to seatedpositions (FIG- URE 2) against surface 33 and thereby insure againstupward movement of the tubing hanger 31.

The multi-purpose element 22 is formed, above flange 32, with atleast'one and preferably several side-outlet connecting conduits $8which are illustrated as being of the flanged type having radial flanges39 at their outer ends. Referring to FIGURE 3, it is pointed out that inthe illustrated embodiment the side-outlet conduits 38 are diametricallyopposite each other and are spaced approximately forty-five degrees fromthe adjacent boss por tions 37 for lock screws 36. The extreme upper endor rim of the multi-purpose element 22 is internally threaded at 41 toreceive the correspondingly-threaded wide end portion of a swaged nipple42. The upper and smallerdiameter end of the swaged nipple 42 isinternally threaded to receive elements employed during bothflowoperation and pumping-operation of the well, as will be describedsubsequently. The swaged nipple constitutes a cover means (including aplug) for the multi-purpose element.

As previously indicated, the annulus 43 between casing strings 12 and 16is sealed off by means of the elastomeric packing element 21. This iseffected either by tightening of the cap screws 26 to compress the ring21, or by hanging of the tubing string 23 so that the Weight of thestring is transmitted to the packing rubber 21 to compress the same, orby both of these means acting in combination. If desired, a seal may beprovided around the upper end of easing string 16, as indicated at 44.Such seal may be of the type in which viscous sealing material isintroduced under pressure around a ring. I

The annulus 43 is vented through openings 45 located adjacent taperedbowl 13. A vent opening for the inner annulus is provided in themulti-purpose element 22 between the shoulders 28 and 29, and isnumbered 46 (FIG- URE' 3). Opening 46 is suitably threaded to receive aflanged elbow 47 or other conduit element.

The above-indicated inner annulus (numbered 48) between tubing string 23and casing string 16 is suitably sealed by means of a sealing ring 49mounted in the upwardly-facing shoulder portion 29 of element 22. Seal49 acts in combination with seals 44 and 21. In addition to theabove-indicated seals for the various annuluses, a seal is providedaround each lock screw 36 in the form of a sealing ring 51 held in placeby a threaded plug 52. Leakage of well-fluid from the chamber 53 definedby the swaged nipple 42 and also by the upper portion of multipurposeelement 22 (above hanger flange 32) is thus prevented.

Operation Let it be assumed that the second casing string 16 has beenrun into the well and cut off in generally the same plane as the upperend of base head body it such casing string being supported by slips 14as previously indicated. The lower snap ring 19 is then inserted and thelower packer plate 18 is supported thereon. It is then merely necessaryto mount the packing rubber 21 and multi-purpose element 22 in place, asstated above, and to insert the cap screws 26 through the openingstherefor and thread them into the openings in lower packer plate 18.This seals the outer annulus 43.

The tubing string 23 is then run into the well and is supported by thetubing hanger 31, the flange 32 of the latter resting on the shoulder 29of element 22 as previously described. The weight of the tubing stringis thus transmitted through element 22 to the packing rubber 21 forannulus 43, and supplements or replaces the eifect of cap screws 26 inmaintaining packing rubber 21 compressed. The lock screws 36 arethreaded inwardly until the ends 34 thereof are seated against conicalshoulder 33, so that upward shifting of the tubing hanger due to factorssuch as unusual pressures in annulus 48 is prevented. The swaged nipple42 is threaded into internally-threaded upper portion 41 of element 22.

Let it next be assumed that the particular well is of the type whichflows, during a period subsequent to drilling, due to its naturalpressure and in the absence of pumping. Referring to FIGURE 1, asuitable valve 54 is threaded into the upper and smaller-diameter end oiswaged nipple 42 and is normally maintained in closed condition. Asecond valve 55 is connected to the flanged elbow 47, and a third valve57, of the one-way or checkvalve type, is connected in series with valve56. Check valve 57 is connected through an additional flanged elbow to aT 58 which, in turn, is connected to the flow line (unshown) and also toa third valve 59. Valve 59 is connected to one of the side-outletconduits 3S communicating with chamber 53. The connections between thevarious elements are illustrated as being of the flanged varietyincorporating suitable API rings, but they may be of other suitabletypes. A pressure gauge 61 is shown as being connected to the otherside-outlet conduit 38 from chamber 53.

The valve 56 communicating with inner annulus 48 is normally maintainedclosed. The valve 59 communicating with chamber 53 is normallymaintained open. Well fluid thus passes upwardly through the tubingstring 23 into chamber 53, and thence laterally through the sideoutletconduit 38 and open valve 59 to T 58 and the flow line. When it isdesired to vent annulus 48, valve 59 is closed and valve 56 is opened,so that gas flows through opening 46 (FIGURE 3) and elbow 47, valve 56,check valve 57 and T 58 to the flow line. Check valve 57, which isadapted to permit flow only in a direction from the casing head to theflow line, insures against entrance of production fluid into annulus 48.

When the pressure in the well is reduced to such an extent that the wellceases to flow sufliciently, so that pumping becomes necessary, it ismerely required to remove the valve 54 and introduce a pump and a stringof sucker rods downwardly through the swaged nipple 42,

tubing hanger 31 and tubing string 23. A stuffing-box assembly 63(FlGURE 4) is sealing mounted around the polished rod 64 at the upperend of the string of sucker rods (unshown) to prevent leakage ofproduction fluid from chamber 53. Pumping operation is then comrnenced,and the production fluid flows upwardly through tubing 23 and out theside-outlet conduit 33 and valve 59 to the flow line as in the case offlow operation.

From the above it will be understood that the well may be converted fromflow operation to pumping operation without the necessity of disturbingthe Christmas tree (or equivalent thereof) in any way. Furthermore, thepresent apparatus makes it possible to pull the tubing withoutdisturbing the Christmas tree, this being accomplished by retracting thelock screws 36 outwardly, removing the swaged nipple 4-2 frommulti-purpose element 22, making a threaded connection with the upperportion of tubing hanger 31, and then lifting the tubing out of thewell.

Because of the fact that the well may be converted from flow operationto pumping operation without disturbing the Christmas tree, and becauseof the fact that the tubing may be pulled Without disturbing theChristmas tree, there is no danger that API rings will be damaged sothat the apparatus will leak when the assembly is again made. Thepresent apparatus also makes it substantially safer to pull the tubing.If the well starts to flow while the tubing is being pulled, it ismerely necessary to plug the upper end of multi-purpose element 22. TheChristmas tree is never laid down and out of position.

The present apparatus is also substantially cheaper and more compactthan conventional wellhead apparatus. The need for an adapter flange andcross is eliminated, thus saving a substantial amount of money both formaterials and labor.

Various embodiments of the present invention, in addition to what hasbeen illustrated and described in detail, may be employed withoutdeparting from the scope of the accompanying claim.

We claim:

A wellhead incorporating a combination tubing head and upper packermember, which comprises a generally tubular base head body having legswhich are adapted to be anchored to and supported on a mass of concreteat the wellhead of an oil well, said base head body being telescopedover and welded to a first and outer string of casing, said base headbody having an interior downwardly-convergent frustoconical portionlocated above the upper end of said first string of casing, said basehead body also having at least one vent opening therethrough andcommunicating with said frustoconical portion. a plurality of slipsseated in said base head body on said frustoconical portion thereof. asecond and inner string of casing telescoped into said base head bodyand into said first string of casing and supported by said slips, beinggrooved to permit communication between the annulus defined between saidfirst and second casing strings and said vent opening in said base headbody, a snap ring mounted interiorly in said base head body above saidslips, a lower packer ring seated on said snap ring and extendingbetween the outer surface of said second string of casing and the innersurface of said base head body, said lower packer ring being formed ofrigid material and having an upper horizontal surface, said lower packerring having a plurality of vertical threaded bores therein, a packingrubber seated on said horizontal surface of said lower packer ring andextending between the outer surface of said second casing string and theinner surface of said base head body, said packing rubber having borestherethrough registered with said threaded bores in said lower packerring, a multi-purpose element having a horizontally-disposedradially-outwardly extending flange portion seated on the upper surfaceof said packing rubber and extending between the outer surface of saidsecond casing string and the inner surface of said base head body, saidmulti-purpose element having a generally tubular body extending upwardlyto a region above the upper end of said second casing string, saidtubular body having a radial internal shoulder formed therein, aside-outlet conduit communicating with said multi-purpose element abovesaid radial shoulder, a plurality of cap screws extended downwardlythrough holes in said flange portion of said multi-purpose element andthrough said bores in said packing rubber and threaded into saidthreaded bores in said lower packer ring, said cap screws being adaptedto be tightened to compress said packing rubber between said flangeportion and said lower packer ring, portions of said screws at saidflange portion being unthreaded to permit downward movement of saidmulti-purpose element due to the weight of the tubing string, a secondsnap ring mounted interiorly of said base head body adjacent the uppersurface of said flange portion of said multi-purpose element, a tubinghanger having an internal passage therethrough and having a radiallyoutwardly-extending hanger flange at the upper end thereof, said hangerflange being seated on said internal shoulder in said multi-purposeelement, seal means provided between said radial flange and saidmulti-purpose element, a plurality of lock screws inserted through saidmulti-purpose element and engaged with said hanger flange to maintainthe same seated on said internal shoulder, the upper end of saidmulti-purpose element being internally threaded to receive the wide endof a swaged nipple, a swaged nipple threaded into said upper end of saidmulti-pnrpose element and having a swaged-down upper end, said upper endbeing internally threaded to receive a pipe, said internally-threadedupper end of said multi-purpose element being sufliciently large topermit upward withdrawal of said tubing hanger therethrough upon outwardshifting of said lock screws, and a string of tubing threadedlyassociated with said tubing hanger to deliver Well fluid thereto andthus to said swaged nipple and said side-outlet conduit, the weight ofsaid tubing being transmitted through said multi-purpose element to saidpacking rubber for compression thereof and sealing of the annulusbetween said first and second casing strings.

References Cited in the file of this patent UNITED STATES PATENTS Re.24,609 Johnson Feb. 24, 1959 1,863,890 Wigle June 21, 1932 1,988,442Begg Jan. 22, 1935 2,009,989 Begg July 30, 1935 2,035,834 Penick et a1Mar. 31, 1936 2,042,745 Thompson June 2, 1936 2,096,565 Shaffer et alOct. 19, 1937 2,228,555 Barker Jan. 14, 1941 2,306,102 Penick et a1 Dec.22, 1942 2,417,181 Sandilands Mar. 11, 1947 2,652,895 Arrowood Sept. 22,1953 FOREIGN PATENTS 1,086,643 Germany Aug. 11, 1960 OTHER REFERENCESComposite Catalog, 21st, 1955-56 edition, vol. 3, pp. 4578-81.

